Controller.



PATENTBD Nov. 12, 1907.

P. W. GARRETT. CONTROLLER. APPLICATION FILED .4116.21, 1905.

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UNITED STATES PATEvT oEEioE.

FRANK W. GARRTT, OF NORWOOD, OHIO, ASSIGNOR TO THE BULLOCK ELECTRIC MANU- FACTURING COMPANY, A CORPORATION OF OHIO.

CONTROLLER.

Specification of Letters Patent.

Patented Nov. 12, 1907.

Application filed August 2l. 1905. Serial No. 275.124-

To all whom 'it may camera:

Beit known that I, FRANK W. GARRETT, a citizen of the United States, residing at Norwood, in the county of Hamilton and State of Ohio, have invented certain 5 new and useful Improvements in Controllers, of which the following is a full, clear, and exact specification.

My present invention relates to controllers for electric motors and the object of the invention is to provide a simple and eflicient form of magnetic blow-out for said l controllers. ,l

In carrying out my invention I provide a rotatable drum with contact segments adapted to engage con tact fingers and arrange a blow-out magnet adjacent thereto in such a manner that polar projections from' l said magnet are located between said contact segments and adjacent to the contact lingers. I also prefer to locate a plurality of strips of magnetic material on the opposite side of said fingers and adjacent thereto, preferably mounted on the inner side of the front cover of the controller casing, the arrangement being such that said strips form the return path of the flux of the blowout magnet.

By my improved arrangement the arc which tends to form between the contact finger and its corresponding segment is locatedin a powerful and concentrated field of magnetic force. The arc is therefore ruptured as soon as formed and this is accomplished with a magnet having a smaller number of ampere turns than has heretofore been required to accomplish the same result. I am thus enabled to produce an effective blowout with a simple and inexpensive device which economizes current and is easy to maintain in operative condition.

The invention will be more clearly understood by an inspection of the accompanying drawings, in which Figure 1 is a front elevation of a controller equipped with my improved blow-out construction; Fig. 2 is a sectional plan view on the line 2-2 of Fig. 1; Fig. 3 is a detail section; Fig. 4 is a vertical section on the line 4 4 of Fig. 1; and Fig.. 5 is an elevation of the interior of the front cover of the controller casing.

Referring now to the drawings, the controller casing l0 contains the rotatable member or drum 11 carrying the contact segments 12. The drum, preferably of non-magnetic material, is supported in the bearings 13 and 14 and is provided with the customary notchplate and dog 15, and with an operating handle (not shown). Mounted upon the insulating block 16 are a plurality of contact fingers 17 adapted to engage the projecting contact segments 12.

Located adjacent to the drum 11 is a blow-out magnet the core 18 of which is preferably formed integral with the casing 10 and carries the coil 19. The plate 20 of magnetic material is fastened to the core 18 and carries the strips or polar projections 21 of magnetic 55 material. Said strips 21 project' between the contact segments 12 adjacent to the Contact fingers 17 and are carefully insulated by the insulating material 22, clearly shown in Figs. 2 and 3, from the plate 20. This prevents the formation'of arcs between the said polar 60 projections and the contact fingers or segments. Located on the opposite side of said fingers and forming a return path for the flux of the magnet is a strip or strips 23 of magnetic material. I have here shown these strips equal in number to the contact fingers, each strip 23 having one end located directly back of its corresponding linger. The strips are preferably mounted parallel to each other on the inner surface of the front wooden cover 24 of the controller casing (Fig. 5). If the front cover is of metal, said strips 23 70 should be carefully insulated therefrom. The end of each strip 23 adjacent to the 'contact finger is bent toward the contact linger and is provided with a cap or cover 25 of insulating material, and the opposite end 23 of said strip is in contact or almost in contact with 75 the iron controller casing 10.

The path of the magnetic ux from the blow-out magnet is as follows: from the core 18, through plate 20, polar projections 21, across the gap between the projections 2l and the strips 23, thence through the latter 80 and the controller casing l0 to core 18. It will thus be seen that I obtain a concentration of magnetic flux just at the point of engagement between cach Contact linger and its corresponding segment, and that any arc which tends to form at this point between the finger and segment is immediately ruptured by the powerful concentrated flux.

In the appended claims I aim to cover all modifications of my invention which do not depart from its spirit and scope.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent isj 1. In a controller, a plurality of Contact fingers, a rotatable drnm carrying contact segments adapted to engage said contact fingers, and a blow-ont magnet having a plnrality of polar projections of like polarity located between said segments adjacent to said fingers.

2. In a controller, a plurality of contact fingers, n rotatable drinn carrying contact segments adapted to engage said contact fingers, a blow-out magnet having a plurzilty of polar projections of like polarity located between seid segments adjacent to said fingers, and a plurality of strips of magnetic material also adjacent to said fingers and forming the return paths for the flux of said magnet.

3. In a controller, a plurality of contact fingers, a rotatable drum carrying contact segments adapted to engage said contact fingers. a blowout magnet having a plurality of polarprojections located between said segments adjacent to said ,finger-s, and a cover for said controller carrying a plurality of'. strips of magnetic material adjacent to said contact fingers, said strips forming the return paths for the flux of said magnet.

4. In a controller, a plurality of contact fingers, a rotatable drum carrying contact segments adapted to engage said contact fingers, a blow-out magnet having a plurality of polar projections located between said segments adjacent to said fingers, a cover for said controller carry ing a plurality of strips of magnetic material adjacent to said contact fingers, said strips being bent away from said cover toward the fingers and provided at their ends with insulating material.

5. In a controller, a plurality of contact fingers, a rotatable drum carrying contact segments adapted to engage said Contact fingers, a blow-out rmagnet having a plurality of polar projections located between said segments adjacent to said fingers, and a plurality of strips of magnetic material also adjacent to said fingers and forming the return paths for the flux of said magnet, each of said strips being behind a contact finger and the polar projections being suhstantially in front of said finger, the arrangement being such that the arc which tends to form between the contact finger and its corresponding segment is located in the path of the flux in the gap between one of the polar projections and one ot said strips.

y6. In a controller, a drum having contact segments projecting therefrom, contact fingers adapted to engage said segments, a blow-out magnet having polar projections of like polarity located between said projecting segments adjacent to said fingers, and a member or members of magnetic material located on the opposite side of said fingers and forming a return path for the fiux of said magnet.

7. In a controller, a. drum having contact segments projecting therefrom, contact fingers adaptedto engage said segments, a blow-out magnet, a plate o! magnetic material fastened to the core of! said magnet, and 'a plurality of strips of magnetic material fastened to said plate, but insulated therefrom and projecting between said segments adjacent to said contact finger.

S. In a controller, a drum having contact segments projecting therefrom, contact fingers adapted to engage said segments, a blow-out magnet, a plate of magnetic material fastened to the core of said magnet, a plurality of strips of magnetic material fastened to said plate, but insulated therefrom and projecting between said segments adjacent to said contact finger, and a plurality of strips ot magnetic material located on the-opposite side of said lingers and forming the return path for the flux of' said magnet.

l). In a controller, 'a controller casing. a front cover therefor of non-magnetic material, a blowout magnet, and a 'plurality of strips of magnetic material carried by said cover and forming part of the path ot' the flux from said magnet.

10. In a controller, relatively fixed and movable coperating contacts, a blow-out magnet, a controller casing, a front cover therefor of non-magnetic material, and a strip or strips of magnetic material carried by said cover and forming part of the path of the flux from said blow-out magnet.

11. In a controller, a plurality of contact fingers, a rotatable drum carrying contact segments adapted to engage said contact fingers, and a single blow-out magnet having a plurality of polar projections located between said segments adjacent to said fingers.

12. In a controller, a plurality 0f Contact fingers, a rotatable drum carrying contact segments adapted to engage said contact fingers, a single blow-out magnet havinga plurality of polar projections located between said segments adjacent to said fingers, and a plurality of strips of magnetic material also adjacent to said fingers and forming the return paths for the fiux of said magnet.

13. In a controller, a plurality of.' contact fingers, a rotatable drum carrying projecting contact segments adapted to engage said contact fingers. and a blow-out magnet havlng a plurality of polar projections from one of its pole pieces, said projections alternating with said projecting segments and located adjacent to said fingers.

14. In a controller, a controller casing, a front cover therefor, a blow-out magnet, a single controlling drum, and a plurality of strips of magnetic material carried by said cover adjacent to said drum and forming part of the path of the flux from said magnet. l

In testimony whereof I aflix my signature, in the presence of two witnesses.

FRANK \V. GARRETT Witnesses SANFOuD KLEiN, FRED J. KiNsnr. 

